There are many commercial and military uses for a mobile facility which can be transported over public highways without a special permit and which can quickly expand to provide a large enclosed interior space with a flat floor. Some sample uses include use as a military field hospital, for use with commercial exhibitions and demonstrations, and working quarters for a temporary job site.
The width of mobile facilities is generally limited by federal regulations governing maximum vehicle width allowable for transport over the public highways. Special permits can be obtained to legally transport oversized vehicles. These permits can add significant cost to the transportation of the oversized vehicle. It is therefore preferable that a mobile facility be not so large as to require special permits.
In order for a mobile facility to posses a greater interior width and floor area than a standard sized trailer, without requiring a special permit, the mobile facility must have some method of expansion. One way of expanding a mobile facility is through the use of a slide-out. A slide-out is essentially a five sided box which can slide out of one side of a facility from a compact configuration to an expanded configuration thereby expanding the interior space of the facility. Slide-outs are often found in recreational vehicles. A slide-out has several disadvantages when used in a mobile facility.
A single slide-out that expands the width of a mobile facility can only expand the width of the facility by an amount less than the initial width of the facility. This is because the expanded width comprising the sides of the slide-out must be contained within the width of the facility when the slide-out is in the compact configuration. Furthermore, if both sides of the facility have typical slide-outs for expansion, the slide-outs must either each expand the sides of the facility only half as much as the facility is wide or else be of different dimensions from one other, so that one slide-out fits within the other. Slide-outs on either side of a facility which are of different dimensions from one another will also lack symmetry and be less aesthetically pleasing than a symmetrical design.
A facility with a slide-out tends to have uneven flooring when the slide-out is extended. This is because the floor of the slide-out must be higher than the floor of the facility in order for the slide-out to fit within the facility. Uneven flooring tends to limit the practical applications to which such facilities can be put to use. Uneven flooring presents challenges in moving objects within the expanded interior space and requires extra care when stepping across. This can be especially problematic in applications which require limited lighting, such as certain military applications requiring strict light discipline, or in applications which require the moving about of wheeled objects, such as stretchers in a field hospital.
A facility having a double sided slide-out designed for maximum interior space has the additional problem of a lack of accessibility to the interior of the facility for cargo storage or access when the facility is in the compact configuration. The top most floor in the compact configuration of such a facility is likely to be the floor of one of the slide-outs. Besides problems accessing the cargo hold in this compact configuration, the cargo itself would be stored on the floor portion of one of the slide-outs if the cargo hold was even accessible. Storing cargo on the floor portion of a slide-out in a facility such as this in the compact configuration would likely require cargo of significant weight to be removed prior to expanding the slide-out to avoid damaging whatever mechanism expands or contracts the slide-out. If the cargo is such that it is normally positioned and used in the center of the facility, removing the cargo just to allow the expansion of the slide-outs requires extra time and effort compared to a facility which allows cargo to remain in the center of the facility during the expansion process.
Other expandable mobile facilities may comprise independent panels which must be manually fitted to sections of the facility and locked into position. This type of facility could just as easily be made independent of a trailer or vehicle. Such an expandable facility requires significant time and manpower to setup and tear down. The longer it takes to setup and tear down such a facility, the less mobile it truly is.